Troubleshooting Debian 11

Reference: Systematic approach to troubleshoot and resolve slow performance issues on a Debian 11 1. Immediate Actions If your system is extremely slow, try these first: Recovery Mode: Boot into recovery mode (usually by pressing Esc, Shift, or F2 during boot). This starts the system with minimal services, potentially bypassing the performance issue. Kill Resource-Intensive Processes: If you can access a terminal, use top to identify and stop processes consuming excessive resources: sudo pkill -STOP <process_name>. Clear System Cache: sudo sync && sudo echo 3 > /proc/sys/vm/drop_caches 2. Basic Diagnostics CPU Usage: top (or htop if installed) - Look for processes consistently using a high percentage of CPU. Memory Usage: free -h - Check for low available memory, which could indicate excessive swapping. Disk I/O: iostat - High %util values suggest disk bottlenecks. 3. Rockchip/ARM64 Specific Checks CPU Governor: cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor - Should be performance. If not: echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor Thermal Throttling: cat /sys/class/thermal/thermal_zone*/temp - Check for overheating. 4. Software and Configuration Diagnostics Boot Logs: dmesg | less - Look for errors or warnings during boot. System Logs: journalctl -p err -b - Check for recent errors. For specific services: journalctl -u <service_name>. Package Management Logs: less /var/log/apt/history.log - Review recent installations or updates. less /var/log/dpkg.log - Check for package installation errors. Recently Modified Files: sudo find /etc -type f -mtime -7 -ls (lists files modified in the last 7 days). 5. Advanced Troubleshooting Hardware Checks: sensors (if installed) to monitor hardware temperatures and voltages. Consider running memtester to check for memory issues. Detailed System Information: Install sysstat: sudo apt install sysstat. Use sar to collect detailed system performance data. Live Boot Environment: Boot from a Debian Live USB/SD card to test if the slowdown persists, which could indicate a hardware problem. 6. Prevention Regular Backups: Use timeshift (or similar tools) to create system snapshots: sudo timeshift --create --comments "Before making changes". System Updates: Keep your system updated: sudo apt update && sudo apt upgrade -y. Configuration Management: Use version control (e.g., Git) or dedicated tools like etckeeper to track changes to configuration files. 7. Reconstructing Changes (If Necessary) If the above steps don’t pinpoint the cause, you can try to reconstruct your recent changes: Command History: history Audit Logs (if configured): ausearch -k <event_key>